The Mount Wilson-Santiago Peak measurements (1928)

It is not well known that Santiago Peak in the Santa Ana Mountains was used as part of Michelson’s measuring efforts. I certainly had never heard of it. I first came across it in a brief two paragraph reference on page 319 in the book, “The Master of Light”, a biography by Dorothy Michelson Livingston, Michelson’s daughter. She writes:

“…Michelson now turned his attention to measuring the velocity of light over a far greater distance than had ever been used before. With the aid of his friends at the Coast and Geodetic Survey, the distance between stations on Mount Wilson and Mount San Jacinto, 82 miles away, was painstakingly measured, as was also the distance between Mount Wilson and Santiago Peak 50 miles away.

Neither of these tests gave much promise of success because of the hazy atmosphere and the smoke from constant forest fires…”

Later, going through the Pease and Adams papers at the Huntington Library, I was able to fill in a few, but not all of the details.

Driven by his dissatisfaction with the visibility along the Mount Wilson-San Jacinto line, in March of 1928 Michelson wrote to Adams asking if he had any preference between a station at “Mount Frazier” and “Mount Santiago” (Mount Frazier is today known as Frazier Mountain, elevation just over 8,000′, located in the Los Padres National Forest 60 miles northwest of Mount Wilson and about 7 miles westerly of Gorman. Mount Santiago is today known as Santiago Peak, elevation just over 5,600′, located 46 miles southeast of Mount Wilson). Adams quickly responded that he thought the seeing was good at both, but that Santiago might be better due to the intervening valley floors being lower. He said Frazier is accessible by road and Santiago was nothing but trail for the final miles to the summit. But Adams said he preferred Santiago if there was any chance of getting equipment to the top. Adams told Michelson he would be sending Jones to Santiago by the end of March to check out the location.

In June of 1928, the mirrors and other equipment originally used for the San Jacinto attempt were taken to the Santiago site and installed for testing by Michelson over the Summer. As usual, the press followed Michelson’s activities and reported them (articles below). Unfortunately, as with the San Jacinto installation, despite the larger 40″ mirrors seeing was too poor to perform reliable measurements. Shortly thereafter the equipment was removed from the peak. Today the 40″ mirrors, used for both the San Jacinto and Santiago Peak attempts, are on display in the small museum located in the base of the 100″ telescope dome on Mount Wilson.

Los Angeles Times of Aug 1, 1928 announcing Michelson’s arrival in Pasadena to begin tests of a beam path between Mt. Wilson and Santiago Peak in Orange County.

Huh? Santiago Peak? As I said, that was news to me. I had been on Santiago Peak many times but never noticed anything Michelson-like. I knew it was a veritable antenna farm, providing communications for much of Orange County and the Inland Empire. It was time for a road trip!

Getting to the top of Santiago Peak in a vehicle is always an iffy proposition what with fire or storm damage closures. Finding an open route is sort of like winning a lottery. Finally, on a nice early December day, there was an open route and I headed off to the peak.

Since I had never seen anything like what I had come to expect from Michelson’s equipment mounts on earlier trips to Santiago Peak, I stopped first at Modjeska Peak. It’s adjacent to Santiago Peak, almost as high, and with it forms the “saddle” by which Santiago Peak is also known: Old Saddleback.” My thought was that if Lookout Mountain came to be incorrectly called “Mount San Antonio” in most documentation of Michelson’s efforts, then perhaps a Santiago Peak installation could actually be on Modjeska Peak.

In the case of Modjeska Peak, there’s no current road all the way to the top, so a short hike was involved. There was an antenna or two on a lower flank, but nothing obvious at the top. So it was on to Santiago Peak.

If anything, there was even more massive antennas and foundations than I had seen before. I found it unlikely any evidence of Michelson’s installation might remain. Then off in the bushes, I saw an old slab of concrete lying on its side. It looked like it had been pushed out of the way when some of the communications buildings were constructed.

It certainly looked familiar! The age of the concrete appeared quite old, in line with what would have been used in the 1930s. There was also the same three point mirror attachment arrangements seen on other Michelson installations. The pier looked as if it had just been bulldozed out of the way a number of years ago to make way for new construction. Given the remoteness of the site, it makes sense that it would just be abandoned in place and no effort made to haul this “debris” down the mountain.

Unlike the San Jacinto site, I was unable to find any evidence of a rear pier, although there almost certainly was one at one time. So, while Michelson’s installation in Riverside County gets a nifty bronze plaque, the one in Orange County gets bulldozed off into the brush. A tale of two Counties. It would be nice to do something about that….